Wehner



March 31, 1964 A. WEHNER DEWATERING APPARATUS 2 Sheets-Sheet 1 Filed March l5, 1962 m. u n n H ,All 1 Tl M n T| :LAIILIE wuull,... a 5 1 J au March 31, 1964 A WEHNER DEWATERING APPARATUS 2 Sheets-Sheet 2 Filed March l5, 1962 IN1/Enron M Um ML 1. WM

United States This invention relates to a dewatering rband tor separating solids from sludge containing solids, especially those having ta high proportion of solid constituents present in very tine form, such as occur in particular in the ceramic and chemical industries.

The invention starts from a known construction of an endless dewatering band in which the continuously moved band surface is subdivided by partitions which fold down to form `a succession of troughs. The lateral shutting of of these troughs is effected by a stationary housing in which Ithe band runs while closing them. These foldable partitions 'are pressed progressively on to the band surace by stationary guides which 'approach the band in its running direction, while lat the same time squeezing together and effecting further dew-atering of the material which is present in the troughs and which has previously undergone some dewatering through the permeable band surface.

This known construction of -a dewatering band is improved by the present invention as regards the etliciency achievable 'both quantitatively `and as regards the degree of dewatering lachieved, and its possible uses are widened by a simpliication of the entire construction.

The invention provides the possibility of exerting on the partly dewatered solid constituents of the sludge a pressure effect which is considerably better than with the hitherto known bands, and above all of simplifying and making reliable the process of emptying the trough compartments which in the known arrangements was difficult and did not always proceed with the desired completeness.

These advantages are achieved according to the present invention by closing the compartments formed by the walls ct the housing and the partitions, also at the top by means of closure elements joining together by their upper edges, so that pocket spaces :are Iformed in which the lower, lateral and upper boundaries are linked to each other so that two successive partitions in the course of the folding down process Icarry out predetermined movements dependent on each other in the nature ot an articulated parallelo-gram with progressive diminution of the internal volume of the socket space.

.-The upper closure o-f these pocket spaces may bre formed by single plates attached by hinges or resiliently to the upper Iedges of the partitions. It is of special advantage, however, to use :an endless band running along the housing Wall parallel to the inner supporting band at a distance corresponding to the height of the pocket walls and guided by the wall of the housing, and connected with the upper edges :of all pocket Walls. This band is advantageously guided by rollers provided on the inner surface of the housing or which conversely Iare provided on the band itself and roll on the inner wall of the housing. This method of guiding the outer bands is possible in a specially simple Way, as in the known construction, by impressing vibrations on the band in a direction transversely to its plane by appropriate arrangement or construction of the said guide rollers, or alternatively by using cams or the like, by which the course of the dcwatering process is promoted. :Obviously the inner band may also be led over, or be provided with, such cams or the like for producing vibrations.

According to an important subsidiary feature of the invention, the entirely closed construction lof the compartments makes it possible, in contr-ast to the known construction, to 'allow the band to run on edge about a veri arent tical drum or combination of drums. There is then obtained an entirely new possibility for discharging the dewatered material, which can now take place by the action of gravitational force for which purpose nothing else is necessary than the provision of discharge openings in the housing at a suitable place 'at which the re-erection of the compartments has taken place after passing the guides which fold down the pocket walls. Obviously it is also possible to assist the discharge of the dewatered material from the compartments at the said place by appropriate means, for example by compressed air jets or a plunger acting through the Wall ot' the housing and acting in timed relationship with the band, which is then progressed intermittently, Iand entering into the compartment through a suitable opening while the compartment is stationary for a short time. The emptied pockets, las they move on, are advantangeously rinsed with the filtered water or with fresh Water before being filled with sludge as a following station.

When, in accordance with a special embodiment of the invention, the parti-tions and also the upper covers of the compartments consist of rigid material, they may be provided in a specially advantageous Way with spring inserts which Iact to assist the -re-.crection of the partitions and consequently the opening up of the compartments. The same result can be achieved by providing the side edges of the partitions with lugs which engage with guide rails or grooves in the housing wall in recesses of the partitions which follow such a course that the partitions are successively erected. The inner band, like the outer band, may consist Iof a material which is rigid in lateral direction but exible, as for example spring sheet steel. It is then necessary to provide sealing means at the side edges of the bands against the housing. Such seals, which for the purpose may be made lip-like, are also necessary especially between the horizontal walls of the housing and the edges of the walls of the compartments which slide along inside them.

The whole arrangement is mounted on a permeable bottom plate of the housing so that water can leave at any point. The drum, the housing, or the drum and the housing, may also be made permeable.

In the known arrangements the band preferably runs over two spaced drums, one of which is driven. The pressure producing a dewatering action, which is eX- erted on the material in the pockets during the phase while the pocket spaces are passing the constricted region, can be regulated by making at least one drum displaceable in the `lateral direction so that it can bc moved towards or away from the wall of the housing concerned. To prevent any large particles of solid contained in the sludge giving rise to difficulty in the constricted region, it is advantageous to provide the drum running in this region with a resilient mounting in known manner. For the same reason, the outer guide wall may be made springily flexible.

It is also possible to use only one small driven drum and to replace the other, main, drum by a rigid guide bent in an arc of a circle; the inner band must then be provided with rollers which run on this surface.

Obviously the dewatering effect can be improved by connecting the housing and/or the drum (which is then permeable) to a source of reduced pressure.

The invention will now be further described by way of example with reference to the accompanying drawings, in which FIGURE 1 is a partly sectional side elevation of a rst embodiment of the new dewatering band,

FIGURE 2 is a plan corresponding to FIGURE 1, and

FIGURE 3 is a view, similar to FIGURE 2, of a second embodiment.

In FIGURES 1 and 2, I is the inner band, placed on edge, and 2 is the outer band also placed on edge. Partitions 3 between the bands 1 and 2 form, with the bands, compartments or pocket spaces 4. The outer band 2 in the embodiment shown is guided on rollers 6 provided on the inner wall of the housing.

The inner band runs round the drum and a driven or guide roller 14 arranged at a distance therefrom. The entire arrangement is surrounded by a housing 13 which in the region shown on the left in FIGURE 2 runs at first concentric to the drum 5 at a distance determined by the height of the partitions between the inner and outer bands so that the pocket spaces 4 here have a rectangular cross-section. Then this distance diminishes progressively to such an extent that, as may clearly be seen at d', in FIGURE 2, the pocket spaces passing the narrowing intermediate space are decreased to a minimum by progressive folding down of the partitions. The distance between successive partitions remains always the same, i.e. the boundaries of the compartments carry out movements like the displacement of an articulated parallelogram.

In the course of this deformation of the compartments, water contained in sludge fed into the compartments at a feed opening 8 is progressively forced out in known way and according to the embodiment shown discharged mainly through the permeable drum periphery, indicated at 5, or through the permeable bottom of the housing. In the former case the inner band must naturally also be permeable.

Also, as may be seen from FIGURE 2, the shaft '7 of the drum 5 may be laterally displaceable so that it may assume for example the positions 7 and 7 corresponding to a more or less diminished volumetric capacity of the collapsed pocket spaces during passage through the constriction'.

In the embodiment of FIGURES 1 and 2, in which one drum 7 and one driving roller 14 spaced therefrom are provided, the' possibility is present of providing between this drum and roller squeezing rollers 11 by which the partly erected pockets, after having passed the constriction, are pressed together again, i.e. a repetition of the pressing process takes place. The dewatered solids, when the pockets pass an opening 9 in the bottom of the housing, falls downwards by the action of gravitational force and arewithdrawn.

In FIGURE 2, the numeral 12 merely indicates diagrammatically an apparatus which assists the action of gravity in the emptying of the compartments. This apparatus may be means for producing a compressed air jet or an ejecting plunger.

The embodiment according to FIGURE 3 shows the possibility of impressing'vibrations on a band constructed in principle in the same way as that above described, and in fundamentally the same way as is described in German printed application (DAS) No. 1,097,381. The circumference of the drum 5 is given a cam-like profile and the inner band 1 has a corresponding counter-profile.

In FIGURE 3, the numeral 16 indicates the flexible mounting of the drum-in the embodiment shown the support thereof by a spring-in consequence of which the gap in the region of the constriction automatically widens if a larger body passes through it. The resiliently sprung construction of the housing wall in this region indicated at 17 serves the same purpose.

The filtering effect of the dewatering band according to the invention may be utilised in `a specially advantagous way by adding, in known manner, wetting and occulating agents to the sludge.

I claim:

1. In a dewatering apparatus; a housing having at least spaced upper and lower walls and a side wall extending therebetween; a first drum mounted in said housing for rotation about a vertical axis; a second drum mounted in said housing for rotation about a vertical axis and spaced laterally from said first drum; a dewatering band fitting closely the upper and lower walls of said housing and extending over said drums, said band having a continuous inner member and an outwardly spaced continuous outer member, and a series of spaced partitions respectively connecting said inner and outer members; at least a portion of the peripheral surface of said first drum and an adjacent portion of the side wall of said housing defining a constricted region therebetween; said partitions being adapted to fold down progressively as said band is moved through the constricted region between said rst drum and an adjacent portion of the side wall of said housing and continuously between the upper and lower walls of said housing in sealing contact therewith, whereby the compartments formed by the partitions are closed by the side walls of said housing which positively guide the folding down movement of the partitions so that closed intermediate spaces are formed.

2. The invention defined in claim 1 wherein the inner portion of the side wall of said housing is provided with guide rollers for guiding said dewatering band.

3. The invention defined in claim 1 wherein said first drum is flexibly spring mounted.

4. The invention defined in claim 1 wherein said housing is made flexible in the constricted region adjacent said first drum.

5. The invention defined in claim 1 wherein the inner member of said dewatering band and said first drum are liquid permeable.

6. The invention defined in claim 1 wherein the inner member and the outer member of said dewatering band are made laterally stiff and the edges of said band are provided with sealing means.

7. The invention defined in claim 1 wherein the lower wall of said housing is provided with a discharge opening in the region in which complete opening of the compartments is effected.

8. The invention defined in claim 1 wherein means for assisting' emptying of the compartments of said band operate in timed dependence on the movement of said band.

9. The invention defined in claim 1 wherein at a distance from the constricted region and at a place at which partial re-erection of the partitions of said band has taken place, guide means is provided to effect a partial folding down of the partitions.

10. The' invention defined in claim 1 wherein one of said drums is driven, and means for displacing the other of said drums in a radial direction so that it can be moved towards or away from the surrounding housing throughout all the constricted region thereof.

References Cited in the file of this patent UNITED STATES PATENTS (German printed application) 

1. IN A DEWATERING APPARATUS; A HOUSING HAVING AT LEAST SPACED UPPER AND LOWER WALLS AND A SIDE WALL EXTENDING THEREBETWEEN; A FIRST DRUM MOUNTED IN SAID HOUSING FOR ROTATION ABOUT A VERTICAL AXIS; A SECOND DRUM MOUNTED IN SAID HOUSING FOR ROTATION ABOUT A VERTICAL AXIS AND SPACED LATERALLY FROM SAID FIRST DRUM; A DEWATERING BAND FITTING CLOSELY THE UPPER AND LOWE WALLS OF SAID HOUSING AND EXTENDING OVER SAID DRUMS, SAID BAND HAVING A CONTINUOUS INNER MEMBER AND AN OUTWARDLY SPACED CONTINUOUS OUTER MEMBER, AND A SERIES OF SPACED PARTITIONS RESPECTIVELY CONNECTING SAID INNER AND OUTER MEMBERS; AT LEAST A PORTION OF THE PERIPHERAL SURFACE OF SAID FIRST DRUM AND AN ADJACENT PORTION OF THE SIDE WALL OF SAID HOUSING DEFINING A CONSTRICTED REGION THEREBETWEEN; SAID PARTITIONS BEING ADPATED TO FOLD DOWN PROGRESSIVELYH AS SAID BAND IS MOVED THROUGH THE CONSTRICTED REGION BETWEEN SAID FIRST DRUM AND AN ADJACENT PORTION OF THE SIDE WALL OF SAID HOUSING AND CONTINUOUSLY BETWEEN THE UPPER AND LOWER WALLS OF SAID HOUSING IN SEALING CONTACT THEREWITH, WHEREBY THE COMPARTMENTS FORMED BY THE PARTITIONS ARE CLOSED BY THE SIDE WALLS OF SAID HOUSING WHICH POSITIVELY GUIDE THE FOLDING DOWN MOVEMENT OF THE PARTITIONS SO THAT CLOSED INTERMEDIATE SPACES ARE FORMED. 